yggdrasil75/stupidsimcpp
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added fluidsim to main

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yggdrasil75
2026-02-07 08:58:54 -05:00
parent 02361effc5
commit ca226d8c02
5 changed files with 186 additions and 88 deletions
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2
makefile
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@@ -34,7 +34,7 @@ endif
CXXFLAGS = $(BASE_CXXFLAGS) $(SIMD_CXXFLAGS)
# Source files
SRC := $(SRC_DIR)/fluidsim.cpp
SRC := $(SRC_DIR)/g3etest.cpp
#SRC := $(SRC_DIR)/g2chromatic2.cpp
SRC += $(IMGUI_DIR)/imgui.cpp $(IMGUI_DIR)/imgui_demo.cpp $(IMGUI_DIR)/imgui_draw.cpp $(IMGUI_DIR)/imgui_tables.cpp $(IMGUI_DIR)/imgui_widgets.cpp
SRC += $(IMGUI_DIR)/backends/imgui_impl_glfw.cpp $(IMGUI_DIR)/backends/imgui_impl_opengl3.cpp

188
tests/fluidsim.cpp
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@@ -13,23 +13,44 @@
#include "../stb/stb_image.h"
int main() {
struct fluidSimPreviewConfig {
float lodDist = 4096.0f;
float lodDropoff = 0.001f;
bool slowRender = false;
int outWidth = 1024;
int outHeight = 1024;
int rayCount = 1;
int reflectCount = 1;
bool globalIllumination = false;
bool useLod = true;
};
class FluidSimUI {
private:
fluidSim sim;
// Simulation settings
const int TOTAL_FRAMES = 10000;
const int WIDTH = 1024;
const int HEIGHT = 1024;
// Setup Camera
fluidParticle baseParticle;
fluidSimPreviewConfig viewConfig;
Camera cam;
// UI State
bool isRunning = false;
int particlesToSpawnPerFrame = 2;
int totalParticleCap = 5000;
// Texture Management
GLuint textu = 0;
std::mutex PreviewMutex;
bool updatePreview = false;
bool textureInitialized = false;
frame currentPreviewFrame;
public:
FluidSimUI() {
cam.origin = Eigen::Vector3f(0.0f, 4000.0f, -5800.0f);
cam.direction = (Eigen::Vector3f(0.0f, 0.0f, 0.0f) - cam.origin).normalized();
cam.up = Eigen::Vector3f(0.0f, 1.0f, 0.0f);
cam.fov = 60.0f;
// Base particle template
fluidParticle baseParticle;
baseParticle.velocity = Eigen::Vector3f::Zero();
baseParticle.acceleration = Eigen::Vector3f::Zero();
baseParticle.forceAccumulator = Eigen::Vector3f::Zero();
@@ -37,64 +58,113 @@ int main() {
baseParticle.viscosity = 8.0f;
baseParticle.restitution = 200.0f;
std::cout << "Starting Fluid Simulation..." << std::endl;
sim.grid.setLODFalloff(0.001);
sim.grid.setLODMinDistance(4096);
sim.grid.setLODFalloff(viewConfig.lodDropoff);
sim.grid.setLODMinDistance(viewConfig.lodDist);
}
for (int frameIdx = 0; frameIdx < TOTAL_FRAMES; frameIdx++) {
if (frameIdx < (TOTAL_FRAMES * 0.1f)) {
if (frameIdx % 1 == 0) {
//float t = static_cast<float>(frameIdx) / (TOTAL_FRAMES * 0.9f);
int spawnCount = 2; // + static_cast<int>(t * 4);
sim.spawnParticles(baseParticle, spawnCount);
~FluidSimUI() {
if (textu != 0) {
glDeleteTextures(1, &textu);
}
}
void update() {
if (isRunning) {
if (sim.getParticleCount() < (size_t)totalParticleCap) {
sim.spawnParticles(baseParticle, particlesToSpawnPerFrame);
}
sim.applyPhysics();
if (frameIdx % 100 == 0) {
std::cout << "Rendering Frame " << frameIdx << " / " << TOTAL_FRAMES << std::endl;
frame renderedFrame = sim.grid.renderFrame(cam, HEIGHT, WIDTH, frame::colormap::RGB, 4, 5, true, false);
std::stringstream ss;
ss << "output/frame_" << std::setw(4) << std::setfill('0') << frameIdx << ".bmp";
BMPWriter::saveBMP(ss.str(), renderedFrame);
} else if (frameIdx % 25 == 0) {
std::cout << "Rendering quick Frame " << frameIdx << " / " << TOTAL_FRAMES << std::endl;
frame renderedFrame = sim.grid.renderFrame(cam, HEIGHT, WIDTH, frame::colormap::RGB, 1, 1, true, false);
std::stringstream ss;
ss << "output/frame_" << std::setw(4) << std::setfill('0') << frameIdx << ".bmp";
BMPWriter::saveBMP(ss.str(), renderedFrame);
} else if (frameIdx % 5 == 0) {
std::cout << "Rendering ultrafast Frame " << frameIdx << " / " << TOTAL_FRAMES << std::endl;
frame renderedFrame = sim.grid.fastRenderFrame(cam, HEIGHT / 2, WIDTH / 2, frame::colormap::RGB);
renderedFrame.resize(HEIGHT, WIDTH, frame::interpolation::NEAREST);
std::stringstream ss;
ss << "output/frame_" << std::setw(4) << std::setfill('0') << frameIdx << ".bmp";
BMPWriter::saveBMP(ss.str(), renderedFrame);
}
if (frameIdx % 500 == 0) {
sim.grid.printStats();
}
}
sim.grid.printStats();
frame renderedFrame = sim.grid.renderFrame(cam, HEIGHT, WIDTH, frame::colormap::RGB, 5, 7, true, false);
void renderUI() {
ImGui::Begin("Fluid Simulation Control");
std::stringstream ss;
ss << "output/frame_" << std::setw(4) << std::setfill('0') << TOTAL_FRAMES << ".bmp";
BMPWriter::saveBMP(ss.str(), renderedFrame);
if (ImGui::Button(isRunning ? "Pause" : "Start")) {
isRunning = !isRunning;
}
ImGui::SameLine();
if (ImGui::Button("Step")) {
sim.applyPhysics();
}
ImGui::SameLine();
if (ImGui::Button("Reset")) {
std::lock_guard<std::mutex> lock(PreviewMutex);
sim.reset();
}
std::cout << "Simulation Complete." << std::endl;
FunctionTimer::printStats(FunctionTimer::Mode::ENHANCED);
return 0;
}
ImGui::Separator();
ImGui::Text("Particle Management");
ImGui::DragInt("Spawn Rate (per frame)", &particlesToSpawnPerFrame, 1, 0, 100);
ImGui::DragInt("Max Particles", &totalParticleCap, 10, 0, 50000);
ImGui::Text("Current Particles: %zu", sim.getParticleCount());
if (ImGui::CollapsingHeader("Physics Parameters")) {
ImGui::DragFloat("Smoothing Radius", &sim.config.SMOOTHING_RADIUS, 1.0f, 100.0f, 5000.0f);
ImGui::DragFloat("Rest Density", &sim.config.REST_DENSITY, 0.00001f, 0.0f, 0.01f, "%.6f");
ImGui::DragFloat("Timestep", &sim.config.TIMESTEP, 0.001f, 0.001f, 0.1f);
ImGui::DragFloat("Gravity (Attraction)", &sim.config.G_ATTRACTION, 0.1f, 0.0f, 500.0f);
ImGui::Text("Base Particle Properties");
ImGui::DragFloat("Viscosity", &baseParticle.viscosity, 0.1f, 0.0f, 50.0f);
ImGui::DragFloat("Restitution", &baseParticle.restitution, 1.0f, 0.0f, 1000.0f);
}
if (ImGui::CollapsingHeader("View Settings")) {
ImGui::DragFloat("Camera FOV", &cam.fov, 1.0f, 10.0f, 170.0f);
float camPos[3] = {cam.origin.x(), cam.origin.y(), cam.origin.z()};
if(ImGui::DragFloat3("Camera Pos", camPos, 10.0f)) {
cam.origin = Eigen::Vector3f(camPos[0], camPos[1], camPos[2]);
cam.direction = (Eigen::Vector3f(0.0f, 0.0f, 0.0f) - cam.origin).normalized();
}
ImGui::Checkbox("High Quality Render", &viewConfig.slowRender);
if (viewConfig.slowRender) {
ImGui::DragInt("Ray Count", &viewConfig.rayCount, 1, 1, 16);
ImGui::Checkbox("Global Illumination", &viewConfig.globalIllumination);
}
}
updatePreviewTexture();
if (textureInitialized) {
float aspect = (float)currentPreviewFrame.getWidth() / (float)currentPreviewFrame.getHeight();
float availWidth = ImGui::GetContentRegionAvail().x;
ImGui::Image((void*)(intptr_t)textu, ImVec2(availWidth, availWidth / aspect));
}
ImGui::End();
}
private:
void updatePreviewTexture() {
std::lock_guard<std::mutex> lock(PreviewMutex);
updatePreview = true;
sim.grid.setLODMinDistance(viewConfig.lodDist);
sim.grid.setLODFalloff(viewConfig.lodDropoff);
if (viewConfig.slowRender) {
currentPreviewFrame = sim.grid.renderFrame(cam, viewConfig.outWidth, viewConfig.outHeight, frame::colormap::RGB, viewConfig.rayCount, viewConfig.reflectCount, viewConfig.globalIllumination, viewConfig.useLod);
} else {
currentPreviewFrame = sim.grid.fastRenderFrame(cam, viewConfig.outWidth, viewConfig.outHeight, frame::colormap::RGB);
}
if (textu == 0) {
glGenTextures(1, &textu);
}
glBindTexture(GL_TEXTURE_2D, textu);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, currentPreviewFrame.getWidth(), currentPreviewFrame.getHeight(),
0, GL_RGB, GL_UNSIGNED_BYTE, currentPreviewFrame.getData().data());
updatePreview = false;
textureInitialized = true;
}
};
#endif

16
tests/g3etest.cpp
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@@ -16,6 +16,7 @@
#include "../util/noise/pnoise2.hpp"
#include "../util/noise/pnoise.cpp"
#include "../util/output/aviwriter.hpp"
#include "fluidsim.cpp"
#include "../imgui/imgui.h"
#include "../imgui/backends/imgui_impl_glfw.h"
@@ -337,6 +338,9 @@ int main() {
updateNoiseTexture(noiseState);
FluidSimUI fluidUI;
bool showFluidSim = false;
sphereConf.centerX = ghalf;
sphereConf.centerY = ghalf;
sphereConf.centerZ = ghalf;
@@ -388,6 +392,10 @@ int main() {
deltaTime = currentTime - lastFrameTime;
lastFrameTime = currentTime;
if (showFluidSim) {
fluidUI.update();
}
if (orbitEquator || orbitPoles || autoRotate) autoRotationTime += deltaTime;
if (autoRotateView) autoRotationAngle += deltaTime;
@@ -528,9 +536,17 @@ int main() {
}
ImGui::Separator();
ImGui::Text("Modules");
ImGui::Checkbox("Fluid Simulation", &showFluidSim);
ImGui::End();
}
if (showFluidSim) {
fluidUI.renderUI();
}
{
ImGui::Begin("Planet Preview");
if (worldPreview) {

33
util/sim/fluidsim.hpp
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@@ -11,6 +11,7 @@
#include <cmath>
#include <random>
#include <algorithm>
#include <unordered_map>
#include "../util/grid/grid3eigen.hpp"
#include "../util/output/frame.hpp"
@@ -30,10 +31,10 @@ struct fluidParticle {
struct gridConfig {
float gridSizeCube = 8192;
const float SMOOTHING_RADIUS = 1024.0f;
const float REST_DENSITY = 0.00005f;
const float TIMESTEP = 0.016f;
const float G_ATTRACTION = 50.0f;
float SMOOTHING_RADIUS = 1024.0f;
float REST_DENSITY = 0.00005f;
float TIMESTEP = 0.016f;
float G_ATTRACTION = 50.0f;
};
Eigen::Matrix<float, 3, 1> posGen() {
@@ -170,20 +171,27 @@ private:
std::map<float, Eigen::Vector3f> gradientmap;
public:
gridConfig config;
float closeThresh = 0.01f * config.SMOOTHING_RADIUS;
float closeThresh;
Octree<fluidParticle> grid;
fluidSim() : grid({-config.gridSizeCube, -config.gridSizeCube, -config.gridSizeCube}, {config.gridSizeCube, config.gridSizeCube, config.gridSizeCube}) {
closeThresh = 0.01f * config.SMOOTHING_RADIUS;
grid.setBackgroundColor({0.1f, 0.1f, 0.2f});
gradientmap.emplace(0.0, Eigen::Vector3f(1, 0, 0));
gradientmap.emplace(0.5, Eigen::Vector3f(0, 1, 0));
gradientmap.emplace(1.0, Eigen::Vector3f(0, 0, 1));
}
void reset() {
grid.clear();
idposMap.clear();
nextObjectId = 0;
newMass = 1000;
}
void spawnParticles(fluidParticle toSpawn, int count, bool resize = true) {
TIME_FUNCTION;
toSpawn.mass = newMass;
//float size = toSpawn.mass / 10;
Eigen::Vector3f color = buildGradient(toSpawn.mass / 1000, gradientmap);
for (int i = 0; i < count; i++) {
Eigen::Matrix<float, 3, 1> pos = posGen();
@@ -219,7 +227,6 @@ public:
}
void applyPressure() {
size_t pointcounter = 0;
for (auto& point : idposMap) {
auto node = grid.find(point.second);
if (!node) {
@@ -311,10 +318,11 @@ public:
void replaceLost() {
std::vector<size_t> idsToRemove;
int gridHalfSize = config.gridSizeCube / 2;
for (auto& point : idposMap) {
if (config.gridSizeCube / 2 > point.second[0] > config.gridSizeCube / 2 ||
config.gridSizeCube / 2 > point.second[1] > config.gridSizeCube / 2 ||
config.gridSizeCube / 2 > point.second[2] > config.gridSizeCube / 2) {
if (std::abs(point.second[0]) > gridHalfSize ||
std::abs(point.second[1]) > gridHalfSize ||
std::abs(point.second[2]) > gridHalfSize) {
idsToRemove.push_back(point.first);
}
}
@@ -331,7 +339,6 @@ public:
}
void applyPhysics() {
TIME_FUNCTION;
computeDensities();
applyPressure();
applyViscosity();
@@ -345,13 +352,13 @@ public:
Eigen::Matrix<float, 3, 1> newPos = point.second + (node->data.velocity);
Eigen::Vector3f oldPos = point.second;
if (grid.move(oldPos, newPos)) {
auto newpoint = grid.find(newPos);
idposMap[point.first] = newPos;
}
}
replaceLost();
}
size_t getParticleCount() const { return idposMap.size(); }
};
#endif

5
util/timing_decorator.cpp
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@@ -1,3 +1,6 @@
#ifndef TIMING_CPP
#define TIMING_CPP
#include "timing_decorator.hpp"
#include <cmath>
@@ -113,3 +116,5 @@ void FunctionTimer::printStats(Mode mode) {
void FunctionTimer::clearStats() {
stats_.clear();
}
#endif